Injury of axillary nerve
Encyclopedia
Injury of axillary nerve (axillary neuropathy) is a condition that can be associated with a surgical neck of the humerus
fracture
.
It can also be associated with a dislocated shoulder
or with traction injury to the nerve, which may be caused by over-aggressive stretching or blunt trauma that does not result in fracture or dislocation.
Injury most commonly occurs proximal to the quadrilateral space.
Injury in this nerve causes paralysis (as always) to the muscles innervated by it, most importantly Deltoid muscle. This muscle is the main abductor of the shoulder joint from 18 to 90 degrees (from 0 to 18 by supraspinatus). Injury can result in a reduction in shoulder abduction
. So a test can be applied to a patient with injury of axillary nerve by trying to abduct the injured shoulder against resistance.
The pain from axillary neuropathy is usually dull and aching rather than sharp, and increases with increasing range of motion. Many people notice only mild pain but considerable weakness when they try to use the affected shoulder.
Surgical neck of the humerus
The surgical neck of the humerus is a constriction below the tubercles of the greater tubercle and lesser tubercle.It is much more frequently fractured than the anatomical neck of the humerus. A fracture in this area is most likely to cause damage to the axillary nerve...
fracture
Fracture
A fracture is the separation of an object or material into two, or more, pieces under the action of stress.The word fracture is often applied to bones of living creatures , or to crystals or crystalline materials, such as gemstones or metal...
.
It can also be associated with a dislocated shoulder
Dislocated shoulder
A dislocated shoulder occurs when the humerus separates from the scapula at the glenohumeral joint. The shoulder joint has the greatest range of motion of any joint in the body and as a result is particularly susceptible to dislocation and subluxation. Approximately half of major joint...
or with traction injury to the nerve, which may be caused by over-aggressive stretching or blunt trauma that does not result in fracture or dislocation.
Injury most commonly occurs proximal to the quadrilateral space.
Injury in this nerve causes paralysis (as always) to the muscles innervated by it, most importantly Deltoid muscle. This muscle is the main abductor of the shoulder joint from 18 to 90 degrees (from 0 to 18 by supraspinatus). Injury can result in a reduction in shoulder abduction
Abduction (kinesiology)
Abduction, in functional anatomy, is a movement which draws a limb away from the median plane of the body. It is thus opposed to adduction.-Upper limb:* of arm at shoulder ** Supraspinatus** Deltoid* of hand at wrist...
. So a test can be applied to a patient with injury of axillary nerve by trying to abduct the injured shoulder against resistance.
The pain from axillary neuropathy is usually dull and aching rather than sharp, and increases with increasing range of motion. Many people notice only mild pain but considerable weakness when they try to use the affected shoulder.